Summary

The study compared the effect of four either fresh or force oxidized organic plant oils in diets for juvenile rainbow trout (Oncorhynchus mykiss) in which 47% of conventional LT fish meal protein was substituted by a mixture of 3 organic plant protein concentrates. Fish oil was completely substituted with either organic linseed oil; rape seed oil; sunflower oil or grape seed oil and evaluated based on feed intake, feed utilization, growth and digestibility. None of the plant oils affected feed intake and growth parameters. Organic plant oils had all a positive effect on lipid digestibility as compared with the fish oil based control diet, despite the very different FA profiles. The organic vegetable oils did not undergo autoxidation, as opposed to the fish oil control for which lipid digestibility was significantly negative influenced.